1. Field of the Invention
The present invention relates to a sheath removing unit and an optical fiber-sheath removing device that remove a sheath of a sheathed optical fiber, such as an optical fiber strand and an optical fiber core.
2. Description of the Related Art
When an optical fiber is to be connected to a device, a connector, or the like, a sheath in the vicinity of the tip of the optical fiber needs to be removed so that a bare optical fiber is exposed to the outside (see Japanese Unexamined Patent Application, First Publication No. H09-113732 and Pamphlet of International Publication No. 2002-4998).
An example of a sheath removing unit in the related art is shown in FIGS. 10 to 12 as a tool that removes the sheath.
The sheath removing unit 20 is a unit that removes a sheath 21b of a sheathed optical fiber 21, and includes a sheath removing blade 28.
The sheath removing blade 28 includes a blade pressing plate 22, a semicircular blade 23, a flat blade 24, and a blade receiving plate 25. The blade pressing plate, the semicircular blade, the flat blade, and the blade receiving plate are laminated in this order and integrated.
A notch 22a in which the sheathed optical fiber 21 can be received is formed at the blade pressing plate 22.
The semicircular blade 23 includes a semicircular blade portion 23a. 
The inner diameter of the blade portion 23a is smaller than the outer diameter of the sheath 21b of the sheathed optical fiber 21 and larger than the outer diameter of a bare optical fiber 21a of the sheathed optical fiber 21.
As shown in FIG. 12, the blade receiving plate 25 includes a pressing portion 27 and a base portion 26 including a V-shaped notch 26a in which the sheathed optical fiber 21 is received.
While the sheathed optical fiber 21 is received in the notches 22a and 26a as shown in FIG. 11, the sheath removing unit 20 is made to move in the direction of an arrow in FIG. 11.
Accordingly, the blade portion 23a of the semicircular blade 23 removes the sheath 21b of the sheathed optical fiber 21.
At present, optical fiber-sheath removing devices including the above-mentioned sheath removing unit are generally manual optical fiber-sheath removing devices.
Although this method is convenient, the success rate of the removal of a sheath may vary according to the worker. For this reason, there was room for improvement in working efficiency of the method.
Accordingly, the automation of the device has been examined for the purpose of the solution of this problem.
The shape of a V-shaped groove, which leads an optical fiber to a sheath removing blade, has caused a problem at the time of this examination (see Patent Literatures 1 and 2).
That is, even when a linear optical fiber is led to the V-shaped groove in a sheath removing device including the V-shaped groove, positional deviation occurs between the optical fiber and the sheath removing blade. For this reason, it was difficult to set an optical fiber at an appropriate position on the sheath removing blade.
Furthermore, the size of the latest optical fiber amplifiers has been significantly reduced.
For this reason, an optical fiber received in the optical fiber amplifier may have a small radius of curvature and a tendency to bend in many cases.
Additionally, since an optical fiber is stored while being wound on a bobbin, a tendency to bend may occur in the same manner.
When a sheathed optical fiber 21 having this tendency to bend is treated in the sheath removing unit 20, the sheathed optical fiber 21 might not be positioned at the notches 22a and 26a and a positional deviation might occur.
As a result, there is a concern that breakage will occur at a bare optical fiber 21a due to the semicircular blade 23 and the like when the sheath 21b is to be removed.
Accordingly, an object of the invention is to provide a sheath removing unit that is suitable for specifications of an automatic device or the like and includes a guide capable of accurately positioning an optical fiber, and an optical fiber-sheath removing device including the sheath removing unit.
In particular, an object of the invention is to provide a sheath removing unit and an optical fiber-sheath removing device that can prevent breakage of a bare optical fiber without positional deviation of an optical fiber at the time of the removal of a sheath even when being applied to a sheathed optical fiber having a tendency to bend.